Origin

Early 16th century (sense 2 of the noun): from Latin, literally 'stiffness, numbness', by extension 'electric ray' (which gives a shock causing numbness), from torpere 'be numb or sluggish'. sense 1 of the noun dates from the late 18th century and first described a timed explosive device for detonation under water.

Although we think of a torpedo as speeding through the water towards its target, at the heart of the word's origin is the notion of slowness and paralysis. The electric ray, a sluggish sea fish that lives at the bottom of shallow water, produces an electric shock to capture prey and for defence. Its Latin name was torpedo, from torpere ‘to be numb or sluggish’, source also of torpid (early 17th century), and when first used in English in the early 16th century torpedo referred to this ray. In the late 18th century the inventor of a timed explosive for detonation underwater gave it the name torpedo from the fish, and this is the ancestor of the modern self-propelled underwater missile.

Derivatives

torpedolike

The longtime Boat U.S. member of Alexandria, VA, was one of the judges who reviewed entries, from a one-person sub called Faux Fish, complete with articulating tail, to a red, six-sided torpedo-like sub called Miss FIT.

Its fuselage, elliptical in cross-section and torpedo-like in silhouette, refined the molded-plywood technique devised and patented ten years before.

As custom called for, a week later Irol's body was sealed and loaded aboard a torpedo-like missile and therewith launched toward the Flaming Moon, where other Apathonian royals and war heroes throughout the ages had been laid to rest.